During the past year Phase II, a multivariant analysis to determine the relationship of birthweight as the dependent variable to a large number of antecedent (prenatal) independent variables, has been completed. The examination of a Birthweight Index derived from Phases I and II to determine its predictive value for birthweight-gestational age outcomes is in progress. The final draft of the birthweight-gestational study will be submitted this year. This work is being completed under personal services contracts with J. B. Hardy and E. D. Mellits.